The proposed research consists of five separate studies of the clinical application of Levo-Alpha-Acetylmethadol (LAAM) with heroin addicts. The first two of these studies will evaluate induction strategies. Study I will compare three schedules for street addicts (i.e. non maintenance patients) and Study II will investigate three comparable schedules in methadone maintenance patients who will be crossed-over to LAAM. In each instance, the schedules differ in terms of the use of supplementary methadone or LAAM. The target sample for each study will be 100 patients per group or 300 per study. The remaining three studies will evaluate LAAM as a detoxification agent. Study III will compare three schedules in street addicts using methadone, LAAM daily and LAAM every other day (100 patients per group). Study IV will investigate the usefulness of LAAM as a detoxification agent with methadone maintenance patients. In a sample of 300 patients half will be detoxified with methadone, the other half will be switched to LAAM and after a period of stabilization, detoxified on LAAM. Study V will take advantage of the fact that 600 patients will be inducted onto LAAM in the first two studies and some unknown number will subsequently elect or be forced to detoxify. This will provide an opportunity to compare methadone and LAAM as detoxification agents in this maintenance group. This study is being organized as a five clinic consortium study primarily because of the large number of patients (1200 in all) believed to be necessary to obtain definitive results. Each clinic will contribute 240 patients. All five studies will be double-blind.